Cal. Pub. Res. Code § 25401.5

For the purpose of reducing electrical and natural gas energy consumption, the commission may develop and disseminate measures that would enhance energy efficiency for single-family residential dwellings that were built prior to the development of the current energy efficiency standards. The measures, if developed and disseminated, shall provide a homeowner with information to improve the energy efficiency of a single-family residential dwelling. The commission may comply with this section by posting the measures on the commission’s Internet Web site or by making the measures available to the public, upon request.